Janet Napolitano, who as President Barack Obama's homeland security secretary has one of the broadest and most challenging portfolios of any Cabinet member, announced Friday that she is stepping down to become president of the University of California system.
Napolitano has been a central figure in the debates over immigration and counter-terrorism policies while also managing the government's response to tornadoes, hurricanes and other natural disasters.
Her resignation comes at a critical time for the Obama administration, as Congress debates a controversial bill to overhaul the nation's immigration laws. Napolitano's departure has been in the works for several months, and she plans to leave her post in early September, two administration officials said.